The main objectives are to study regulation of serum anti-DNA antibody (idiotypes=Id) and anti-DNA carrying B cell clones by auto-anti-DNA (Anti-Id) antibody in a human autoimmune state (Lupus) at various stages of disease activity. Same will be tested in relatives of lupus patients and in laboratory personnel exposed to lupus sera. Idiotypic or cross idiotypic nature of the anti-Id and idiotypic heterogeneity will be tested by raising monoclonal anti-DNA idiotypes, monoclonal anti-idiotypes and heterologous (rabbit) anti-idiotypes. These objectives will be achieve by: 1) testing for anti-anti-DNA antibody in sera of patients with SLE during active and inactive states of their disease, in sera of SLE relatives and in normals who are in contact with lupus sera, 2) To prove the idiotypic qualities of the antibody and its regulatory capacity of Id specific B cells, 3) To study the mechanisms by which the anti-Id modulates the Id by i) demonstration and quantitation of T cells with Id or anti-Id receptor specificity, ii) in vitro proliferation of T cells upon binding to the anti-Id and iii) effect of coculturing the anti-Id-activated T cells with autologous B cells on Id sythesis and secretion. We will study 20 SLE patients, 60 relatives, 20 laboratory personnel and 60 controls. Sera to be tested for anti-Id activity will be depleted of anti-DNA antibody by binding to DNA cellulose columns and depleted of DNA by digestion on immobilized DNAse. Depleted sera, their IgG or IgM, their Fab, F(ab)'2, Fc fragments will be tested for their capacity to bind to 125l-F(ab)'2 fragments of anti-DNA. Hetrologous (rabbit) or monoclonal anti-Id will be used in parallel experiments to the auto-anti-Id. Antigen binding site vs. non-binding site (framework) specificity of the anti-Id will be tested. Specificity of the inhibition will be tested by the use of tetanus toxoid instead of DNA or by testing the inhibition by the anti-Id of the bindign of tetanus toxoid to autologous anti-tetanus antibody. Correlation of HLA types of lupus relatives and of laboratory personnel in contact with lupus sera to the presence of cross-reactive anti-Id will be analyzed. The role of genetic and/or environmental factors in network regulation and the role of anti-Id in preventing the expression or expansion of autoreactive cells and antibodies in human lupus will be clarified.